A wonderful fair weather experience enjoyed by many is riding in a convertible automobile with the top down. Weather or driving conditions dictate, however, that there are times when the top is preferably in place over the passenger compartment. During those times, the convertible often falls short of the comfort, particularly acoustically, of regular passenger cars because of noise generated by outside sources, wind noises and even vibration of the top itself. Improvements in the amount of noise perceived by passengers in such vehicles are desired.
Many types of convertible tops have been designed in the past. U.S. Pat. No. 6,340,196 describes a motor-vehicle convertible top having a flexible and waterproof outer layer defining a roof having edges and an inner surface, a pair of sides joined at the edges to the roof, and a rear wall extending between the sides and a rear edge of the roof. A heat- and sound-insulating inner layer of a foamable plastic is bonded directly to the inner surface of the roof and inner surfaces of the sides. The inner layer is described as a polyurethane foam having a Shore D hardness of about 40 and as having a thickness of between 2 mm and 6 mm.